Conveyors of this type are used for different purposes in logistics applications. A conveyor according to the invention may be a drum motor, for example, or a motorised roller having a drum body. Accordingly, a drum body can also be understood to be a supporting tube or outer tube of a motorised roller or roller body.
Drum motors are deployed, for example, in such a way that they are mounted in a frame by means of an axle, which is then attached stationarily in relation to the frame and torque-resistantly to the frame. The drum body rotatably mounted on an axle is driven and made to rotate by means of a drive unit inside the drum body. The drive unit is supported by the axle and is connected to the drum body on the driven side. The drum motor can be used to drive other devices, for example, a conveyor line consisting of a plurality of conveyor rollers, by means of a belt or the like. The drum motor can also be used directly as a conveyor element in a conveyor line and can carry the conveyed item and convey it by rotation of the drum body. One preferred use is to dispose the drum motor as a drive element at the end of a conveyor belt system and to drive a conveyor belt, which is partly wound around the drum body, and to make it move by rotation of the drum body. Another use consists in disposing the drum motor as a drive element in the middle of the lower run, with the conveyor belt being wound partly around and driven by the drum body.
Drum motors with different driving power are known from the prior art. The driving power ranges from about 10 W to 6 KW and can transmit a torque of up to 1000 Nm via the drum body. Due to their particular construction, drum motors are characterised by the specific problem of heat being difficult to dissipate from the drive means, which is disposed inside the drum body for compact construction. For some drum motors with high power ratings, filling the drum body with oil is, therefore, an established technique in the prior art for ensuring that the drum motor remains thermally stable even under heavy loads. However, due to higher levels of efficiency, it is possible in some cases to dispense with filling the drum body with oil even when such components are used. A gearless electrical drum motor having a plurality of electrical stator windings and a shared, permanently excited rotor or an identical number of mechanically connected, permanently excited series of rotors is known from DE 20 2012 000 793 U1. The single electrical stator windings are connected electrically and mechanically in such a way that they can be connected individually or collectively in order to adjust the power of the drum motor to the load requirements.
In contrast to drum motors, motorised rollers for roller drives are generally equipped with a drum body of smaller diameter, referred to here as a drum tube, and typically have a power rating of less than 100 W, typically in the range between 10 and 40 W. Such roller drives are used to carry and convey items in roller conveyor lines. Roller conveyors can be combined with a plurality of idle rollers arranged in parallel, which are driven by the motor-driven conveyor roller via a belt drive or chain drive, as the case may be. In curved roller conveyors, the rollers are arranged with their axes at an angle to each other.
The drum motors and roller drives can be used, for example, to convey pallets, to convey parcels in parcel dispatch centres, to convey containers in depots of various kinds, or for transporting luggage in airports, and in numerous other applications.
The invention is based on the realisation that conveyors must be produced in different lengths according to the field of application, depending, for example, on the size of the items being conveyed or on conditions on the specific premises. According to the prior art, producing conveyors of different lengths is only economical if a limited assortment of conveyors is offered in different, discrete lengths. Fulfilling individual customer wishes concerning the length of a conveyor invariably makes production more complex and expensive, in that customised sizes of conveyor rollers must be designed. This is a general problem that arises, particularly when supplying spare parts for defective rollers, or when small follow-up deliveries are made.